1. Technical Field
This invention relates generally to shaft seals, and more particularly to shaft seal having lubrication retention and debris exclusion features.
2. Related Art
Seal assemblies are well known for providing a dynamic fluid seal between a housing and a shaft, such as may be used in automotive, machine, heavy equipment, construction, agricultural, and industrial applications, for example. Such seal assemblies commonly comprise a rigid carrier for supporting the seal assembly in a bore of the housing and a wear sleeve to provide a running surface for a seal lip of the seal assembly. The seal assemblies function to contain a lubricant, such as oil, on an “oil side” of the seal assembly and to maintain contaminants or debris on an atmosphere or “air side” of the seal assembly.
Numerous prior seals are known wherein a primary lubricant-retention lip is used in combination with a plurality of debris-excluding features which may take the form of shaft-engaging lips, elastomeric excluders, labyrinth passages, and porous filter elements. However, these prior seals can be improved to inhibit the ingress of debris, which can ultimately degrade the performance of the primary seal lip, and to inhibit the egress of lubrication, which ultimately can lead to lubrication leakage, thereby resulting in unsightly oil puddles, such as on driveways and in garages, for example.